Newton's Third
by MikaelaLynn
Summary: "And yet it applies: for every action, there is an equal and opposite reaction." Loki recited. "When the possibilities of an abandoned choice are too tempting to ignore, fate shall bring that story to her lips and breathe into it new life."


**This is complete self indulgence of an idea I've had floating around for a while. In this world, Tony and Loki have already been together for some time.**

* * *

"Ok, giant portals. Been there, done that. Other realms? A little Shakespearean-Elizabethan, but yeah, they're around. Multiple dimensions, though? Alternate realities? That's some Back to the Future shit right there, Loki, and you've got this thing where you lie a lot..."

Loki took a breath, tolerant, and leveled patient green eyes on his lover. Tony Stark was situated underneath one of his many mechanical carriages, his legs sticking out from beneath it as the faint sound of metal on metal echoed out from his work. The robot, DUM-E, was hovering nearby with a red canister purposed for extinguishing fires. It had already been scolded a number of times for doing so - "I'm telling you, you hunk of junk, I'm not going to set myself on fire fixing my Porsche. Put that-no, no, don't you point that at me. I'll donate you to a city college, I swear." - but yet it remained at the ready near it's master, ever loyal in dedication.

It was odd how devoted Tony's creations were to him, Loki mused. How human-like the machines had become over their time with their Master. Even the voice that ever followed Tony was meant to be a servant, without self-thought or awareness. But it was sentient, Loki knew, and simply lacking a body to inhabit. Tony had created life without intending to, and yet he was not even aware of it.

"I speak the truth." Loki insisted from where he sat on the workshop floor, idle hands cradling a tumbler between long fingers, "There are multiple dimensions in all of reality, Anthony. Every decision made will create the opposite, and reality branches out. Your science has a law for that, does it not?"

"Newton's third is about motion, Loki." Tony protested around a wrench between his teeth.

"And yet it applies: for every action, there is an equal and opposite reaction." He remembered the law from one of Midgard's many books, and the words rolled off his tongue. "The simple things of our days are meaningless - a decision between the consumption of bread or sweets would not birth a new reality. But the decisions of paramount? When the possibilities of the abandoned choice are too tempting to ignore, fate shall bring that story to her lips and breathe into it new life."

Tony wheeled himself out from underneath his beloved car, sitting up on the creeper (an odd name for a plank on wheels) to stare at his partner. Loki could see the man's mind working as he considered the words brought before him, skeptical and curious all at once.

"Let's say you're not crazy."

His lip curled in minor amusement. "Theoretically, of course."

"You're theoretically sane, yeah." Tony smiled, pressing the butt of the wrench underneath his chin as he thought. "How would you even prove the existence of alternate realities?"

"Experience." As if there were any other way. "Many things in this universe have attempted to deceive me, but never once have my eyes dared to lie."

The engineer's eyebrows shot up, as they always did when something caught his attention. It was a familiar expression, and one Loki almost found endearing. That was the face that asked for a story, for an explanation, and for knowledge. And, oh, did Loki have knowledge.

"You have heard the tale of my time as Asgard's King, no doubt."

It was a bitter subject, but one that had no doubt been shared by his oaf of a brother. His friends would have been curious why blood and turned on blood, brother fighting brother, and Thor would have told them. Softened the blow by easing some of the more brutal details, perhaps, but spilling secrets from a loose tongue nonetheless.

"Frost giants, sleeping Dad, and falling off rainbows." Tony summarized. Eloquent, as always.

"Indeed." He stared into his glass, examining the amber liquid within. "When I fell, the Bifrost was in flames beneath me. The magic was wild and free, no longer controlled by the AllSeer. I fell into its embrace, expecting death. But alas, the magic decided to spirit me away instead of consuming me. I found myself in the space between the realms - the Void, as it is truly known, where nothing and everything exists."

Loki looked up, finding that Tony had taken a seat next to him. It shouldn't have been so comforting to have the man sitting with him, covered in the grime and dirt of his work, simply listening. But it was. They nursed drinks together in his workshop, as if they had never been enemies.

What a life they lived. A terrible, wonderful existence.

"I wandered." he continued. "Lost things gather in the Void, from all lands and all times, and I indulged in them. I learned ancient magics, only to forget them when I tested my tongue; I passed by forgotten relics and found them stowed in my pockets by invisible hands. Things faded in and out of existence, and an abundant field would turn into an endless nothing before a heartbeat could pass. It drove me mad. It gave me comfort."

"What does this have to do with alternate realities?"

Loki looked up to meet his lover's gaze, knowing why he had interrupted. Neither of them had ever been comfortable with sharing too much, and whenever he indulged in confession Tony always found a point in which to give him an opportunity to stop. An out. A breath in which to realize he could have been saying too much.

Tony Stark was an odd creature like that, empathetic even though he tried for apathy, and Loki was fond of such a strange trait.

"Just before I was taken from the darkness, I heard a whisper that I did not have time to forget." he concluded, "A spell to enchant a looking glass, not so much unlike scrying."

Tony's brow furrowed. "Crystal balls, now? Seriously, man, English."

How he had such patience for this man, he would never know. "Fetch me a mirror, Stark. Words are not needed to explain."

At Tony's hesitance, however, Loki rolled his eyes. With a flourish of his hand, a mirror faded into existence before them, hovering inches off the ground. Tony stared in it and his reflection stared back, concern and curiosity written on his features.

"I thought we said no magic in the shop." It was an empty protest. As Loki stood, so did Tony, and the mechanic stepped forward to touch the polished surface.

"If I show you this, you may not like what you see." His warning was true and sincere, spoken in velvet tones. "I have stepped through the looking glass once, Anthony. I have had no inclination to experience it again."

Despite speaking warnings, he already knew the answer Tony would give him. The man was addicted to knowledge, with an endless hunger to learn all that there was. Once his known world had been shattered by the portal in New York, he had been insatiable.

"What would I see?"

Loki paced to stand behind him. Calm hands fell onto Tony's shoulders, careful fingers pressing between shoulder blades. As always, the man leaned back in fractions, giving into the touch.

"Yourself. You, having made the other choice."

"Not becoming Iron Man."

He nodded at the guess. "Or choosing another path to walk."

He watched Tony's jaw tense at this, looking at his reflection on the mirror's surface. There were ghosts in his eyes, ghosts Loki had never been fond of, and pain. Fear, too. His hands moved in more comforting strokes, loosening the knots of stress forming in his muscles.

"Pay it no thought." Loki decided, stepping forward and placing his hand on the glass. "We will explore my realities."

Brown eyes met green in the reflections, and the darker ones held surprise. Relief was there, too, in the way his face relaxed and his lips parted for breath. Tony stepped back, collecting himself, and gestured at the mirror as if to say, well, get on with it. A familiar display of apathy and dismissal to combat emotion. Anthony Stark was just another book to read, and Loki knew all the lines by heart.

His focus changed and he met his own gaze in the mirror, taking a deep breath to prepare himself. Then ancient words spilled from his lips and the workshop lights flickered, a green haze enveloping his lean form. The mirror's surface rippled beneath his hand and he inhaled, reaching his hand out to his lover. Tony took his hand out of habit, then down they tumbled, falling through the surface of the looking glass.

* * *

It was like the Void, as Loki remembered it. Cold, endless nothing, stretching on forever.

But this time, he was not alone.

Tony's hand was still held tight in his own, yes, but there were others to speak of. Other Lokis, all standing like illusions, blinking in and out of reality. There were too many to count, but many paid the pair little mind. They mingled in the back, green and gold images gleamed from other realities, neither here nor there.

Those who were here , however, were the ones to fear.

"Loki..."

"Now is not the time for words, Tony." The real Loki spoke, his lover's preferred name slipping off his tongue, "Know that you will be the only being in the nine realms to experience this."

He let go of his hand as he stepped forward, but a green thread of magic was left behind, encircled around both their wrists. It was so they would not be separated if the magic faltered. Insurance, Tony might have said. But whatever Tony might have said or would say did not matter in this moment. No, Loki mattered. All of them.

"Which one are you?"

A younger iteration of himself spoke, who stood with the confidence of one who had suffered few pains. Golden horns were upon his brow, but these ones were small, veiled by a tuft of dark hair that fell loose around his face. A handsome Loki, a youthful Loki, a Loki who looked so terriblygood.

The original almost cringed to see himself in such a way. Loki should never be good.

"The one who fell."

Young-Loki nodded and smiled, crossing his arms as if this was all he need to know to understand. A lazy finger gestured towards Tony.

"Stark? Really?" he laughed, but his tone was kinder, "Not bad."

Another Loki stepped forward from the crowd, older than the youngest but not as old as the original. Where young-Loki had varied in minor ways, be it the curve of his jaw or the tone of his voice, this Loki was a copy of the first. Milder, with hair short and slicked back. He did not speak, but he did not have to.

"Look upon him, Stark." Loki murmured, bitterness in his tone. "When I chose to fall, he was born."

"Then he...?"

"I chose to take my brother's hand." Prince Loki answered, nodding.

"Then you?" Tony asked, turning to young-Loki.

"I chose to fight destiny." He answered, cryptic. A smile played on his lips. "I chose to be everything I'm not."

"And I chose to be everything I am." The most terrible Loki spoke those words, slipping into reality as he bled out of a shadow. His features were gaunt and wrinkled, aged with time, and a green suit clung to a lean form. Golden horns arched high from his helm and curved back like a bull's, somehow gleaming when there was no light to be had. "I chose to be the God of Chaos." Then he cackled, the laugh maniacal and cold.

It was enough to make young-Loki cringe and turn away, while Prince Loki shifted uneasily, watching his wicked self with careful eyes. The true Loki gave a grim smile, side stepping to stand between this older iteration and Tony. But four active Lokis became five, and the fifth held a dagger to Tony's throat.

"And I chose to win. " The Loki of New York stood with Iron Man in his bloody grip, a shining dagger to his throat and a crazed grin to his lips. Like the Prince, he shared the original's face, but madness had consumed this one completely. "In my reality, Man of Iron, I bled you dry. But only first after visiting your sweet woman, who tasted like fire and screamed like a harpy, and then I bade you to quarter her with your own bare hands. And oh, did she cry, wanting for you to save her." The dagger dug deeper in his throat. "How she wept when she realized that you would be her executio-"

The first threw a dagger and Loki-victorious disappeared, leaving only a few displaced stands of hair behind and a red line on Tony's neck.

"Shit." Tony was pale and shocked, hand moving to his neck. But he shook his head, insisting he was fine. "Just a little razor burn."

Loki-victorious laughed as he blinked back into vision, his eyes a blazing Tesseract-blue as he stood at the God of Chaos' side. When he spoke again, he spoke to his opposite.

"Oh, and you must have chosen mercy for the humans. He appealed to your humanity and you crumbled, weak and homesick." He mocked the original. "You lost your purpose and forgot the glory. How they fell, brother. How they knelt and cried and begged for freedom. And, yes, did I free them. I, their merciful King." He twirled his spear his hand, pacing behind his other-selves and smiling. "The rivers ran red. Hel's halls overflowed. And Thor..." With a sigh, this Loki looked towards the sky in fond memory. "He cried, brother."

"You are not my brother." The original murmured, standing close at Tony's side.

"No." Loki-victorious smiled. "That I am not." He cleared the distance between them with long strides, bringing the point of his spear to rest against Loki's jaw. "I am you. A better you."

"Quiet, you." A new Loki spoke, with a voice so foreign. It was heavy and accented, worn with age and frost. "None of us are better than the last."

Real-Loki heard Tony's sharp intake of breath and closed his eyes, already knowing the visage that was before him. Jotunn Loki, who had survived abandonment. Jotunn Loki, whom Odin had not taken as a son. Blue Loki, foreign Loki, true Loki.

Loki-victorious hissed, withdrawing his staff and spinning on a heel to see who dared interrupt him.

"You are the worst of us all." The God of Chaos declared, hands twitching with an itch for blood. "An abomination. A monster."

Loki-victorious did not speak. He threw a dagger, meant to kill, with a true aim. But it passed through the Jotunn harmlessly, fazing through his chest. The Frost Giant stood, no taller than the rest, but somehow more intimidating than them. There was a heavy cloak of furs on his back and a horned helm of polished bone and ice on his head, with no hint of black hair poking out from the edges.

Yet, the only thing Tony could think of to say in the sight of Loki's nightmare was, in all honesty, not all that surprising.

"Bald? Man, that's not a good look on you. Five out of ten, and you're only getting that much because of the cool markings. Sweet crown, too."

Jotunn Loki smiled. Real-Loki's lips curled in distaste, as did the others'. If they all shared one thing, it was their self-hatred, which was now manifested before them.

"...So this is all of you." Tony continued, stepping forward. He rubbed at the green rope on his wrist. "Some of the yous, at least."

Loki-victorious chuckled. "Some more important than others, dear Avenger."

"Some more corrupt. Some more innocent." Young-Loki mused. Another form had appeared behind him, the smallest of them all - a child, cautious and keen, with a covered head and a golden band emblazoned with a V-shaped insignia on his brow. He watched from behind the other youth's form. "But we are all the same. In name."

Loki squared his shoulders, feeling ill at the sight of himself. This was just the beginning, he knew. Worse would come, or perhaps better. But these seven were enough for a lifetime.

"Now you see." he told Tony, "Proof of other selves. Other realities."

"Ah, but he should see himself."

The God of Chaos was laughing, joyful, but he was not the one who had spoken. Another Loki had flickered into existence on the opposite side of Tony, exactly the same as the first. Down to the very way his hair fell, they were the same. Whatever decision had birthed him had been a recent one.

"And you?" real-Loki wondered, tone cold, "I did not see you last I came."

"No. But we are more alike than the others."

He turned to Tony, touching his face. Real-Loki tensed, but the newest iteration gave himself a dismissive wave of the hand.

"Never would I harm him." Tony was still as this new Loki ran a thumb over his lips, looking as if he torn between an instinct to pull away and a want to lean into the touch. "Nay. In my world, he would harm me instead."

The hand fell, and Loki-betrayed turned away. "Yes, he should see himself."

Then ancient words fell from his lips before real-Loki could stop him, and the forms of green and black faded into the darkness.

"What did I...?" But Tony lost his words.

Iron Man was standing before them, battered and worn by war and battle. Hints of red and gold were barely visible, beaten away by violence, and the emotionless mask before them offered no comfort that it might have given before. Mechanics whirred as arms moved up to remove the helmet, blood dripping off the gauntlets with every movement.

When the mask was removed, Tony Stark stared at his opposite. They shared the same face, the same smirk, and even the same goatee, but the eyes...

"Enough."

Loki's form shielded hero-Tony from the sight of his villain self, and a simple push sent them rolling out of the Void. There were already others forming behind them. A Tony lying on the ground, with the black pattern of poisonous Palladium etched across his skin - the Tony that had chosen to submit. A younger Tony, all flashing smiles a wicked grins, who had embraced the weapons of an older Stark Industries. A Tony in Afghan garb, who had convinced the Ten Rings he was a better consultant than prisoner. Teenaged Tony, strung out and listless, who had rebelled against his Father in other ways that engrossing himself in study.

They fell one last time through the looking glass, escaping into the sanctuary of Tony's workshop.

They lay on the ground, still bound by green magic, and stared up at the ceiling together.

"...Well, shit."

Loki sighed at his partner's curse, whispering the words that would make the mirror disappear. Torn at his own actions and shaken by revisiting his past and his potentials, he could say nothing more. Content to stare at the harsh fluorescent lights above them, he took a deep breath. Why did he indulge Stark with such painful games?


End file.
